Undesirable character flipping

Hi all,

I've written a fairly simple script to move a character to a point smoothly; the script also rotates the character smoothly to face the rigidbody velocity. However, I have encountered an issue with the character flipping over rapidly on in z axis, especially at points where the character supposed to be upside down. The script seems to force it's local y to match the world y.

Of course this could be due to how I'm rotating the character, but I would like to know if anybody has any superior methods to accomplish this smooth rotation.

My script:

 public bool _active;
 
 public Transform aim;
 
 public float maximumSpeed, acceleration, agility;
 private float currentSpeed;
 
 private GameObject character;
 
 void FixedUpdate() {
 
     if(_active) {
         
         currentSpeed = Mathf.Lerp(currentSpeed, maximumSpeed, Time.deltaTime);
     
         Vector3 velocity = (aim.position - character.transform.position).normalized * currentSpeed;
         
         character.rigidbody.velocity = Vector3.Slerp(character.rigidbody.velocity, velocity, Time.fixedDeltaTime * agility);
         
         character.transform.forward = Vector3.Lerp(character.transform.forward, character.rigidbody.velocity, Time.fixedDeltaTime * agility);
     }
 }